Field of the Invention
The present invention relates to flexible containers for medical use and particularly relates to a method for manufacturing a connector for such flexible bags.
It also relates to an apparatus for implementing this method for manufacturing a connector.
Technical Background
Elements for accessing the content of a flexible bag intended to contain a liquid for medical use in order to fill and empty this bag are known.
Such an access element generally takes the form of a shaft, which is formed by a tube portion being inserted between the two constituent inert plastic walls of the flexible bag and assembling the resulting assembly by binding together at least the peripheral edges of these walls.
One end of this tube portion is in fluid communication with the interior volume of the flexible bag while the other end thereof is placed outside the bag.
To establish liquid communication between the inside of the flexible bag and the outside, an operator then only has to manually insert the end of a connecting piece into this shaft.
To seal the link between the end of this connecting piece and the shaft, it is generally envisaged to position a ring on the inside wall of the shaft defining the liquid passage channel.
This ring which then projects from the inside wall of the shaft into said channel provides an angular linear contact between this wall and the connecting piece.
In addition to sealing the assembly, this contact also limits the effort required for tightening during the assembly of these elements.
The manufacture of such a ring in the inner channel of the shaft is, however, made difficult by the very nature of the materials used in the medical field.
Indeed, these connecting pieces are generally obtained by injecting a thermoplastic material into a mould, spindles being used to define the inner channel for flow of the liquids in these connecting pieces and to define the ring.
Therefore, if the positioning of such a ring in the channel of a shaft formed from a relatively rigid thermoplastic material such as polypropylene (PP) is achievable, it becomes laborious for flexible and/or adhesive thermoplastic materials such as ethylene vinyl acetate (EVA) or EVA derivatives, in particular those compliant with the pharmacopoeia requirements.
Indeed, during the removal of the spindles, there is an extraction of material or the appearance of permanent deformations which require the withdrawal of the shaft formed in this manner.
However, these thermoplastic materials such as EVA tend to stand out compared to the other materials for the manufacture of the elements for storing and conveying liquid for medical use as a result of the inertia thereof in relation to medical solutions, the resistance thereof to radiation sterilisation and the performance thereof at low temperature.
Moreover, producing such connectors from EVA would be particularly advantageous since the availability thereof would allow the manufacture of a flexible bag for medical use produced fully from the same thermoplastic material, and consequently, would make the assembly thereof easier.
The present invention aims to overcome these various disadvantages by proposing a method for manufacturing a connector for a flexible bag for medical use which is particularly simple in the design thereof and in the operating process thereof, which is original in the approach thereof and economical, for producing a ring on the inside wall of the connector without any damage thereof.
Another subject matter of the invention is an apparatus which is original in terms of the architecture thereof for industrially producing these connectors with limited production times.